ALLERGY AND ASTHMA IN THE SOUTHWESTERN UNITED STATES 

Ants 
 
Harvester ants (Pogonomyrmex spp.) and fire ants (Solenopsis spp.) can cause allergic reactions in the Southwest, especially in children.  Harvester ants build "volcano" cones of tiny pebbles at the nest entrance.  Several species of native fire ants are indigenous to the region.  The imported fire ant, which builds very large mounds over their nests, has been extending its range westward, but aside from a single colony, has not yet reached Arizona in significant numbers.   Patients allergic to the imported fire ant may also be allergic to the native species. 
 
 yellow harvester ant image
                                                         Photo courtesy of Hayward Spangler PhD 
 Yellow harvester ant (P. maricopa) - similar to the red harvester ant
P. californicus
)  and measures 7-8 mm.  Fire
ants are half this size. 

More pictures of harvester ants (bugguide.net)

Pictures of fire ants from bugguide.net

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